FLUENT 6 - Solution to highly swirling flow problem - problem of over-predicting tangential velocity near the wall.
|In high-swirl rotating turbulent flows, the default settings for the Reynolds Stress Model and wall function can lead to erroneous predictions of the velocity profiles near rotating walls such...|
MixSim V2.1 - Modeling solids suspension
|The user wants to calculate just suspended velocity using Mixsim. I couldn't find out any reference regarding that calculation in the guide. Also the user wants to know how the beads would...|
POLYFLOW - Pressure build up across a section of twin screw extruder
|For the analysis of flow around screws with the use of the MST algorithm, it is often recommended to select fn=fs=0 as boundary conditions at the inlet and outlet. Does this mean that pressure...|
FLUENT V6 - UDF for accessing field variables at the nodes of a face thread
|It is sometimes necessary to retrieve the values of specific variables at the nodes of your mesh. This could be done by looping over cells/faces and accessing the interpolated data at the...|
POLYFLOW - How to define a Coulomb friction law?
|Coulomb friction law is such that the tangential component of the effort is proportional to the normal component. How can this be defined in POLYFLOW by using the available laws?
The user can...
FLUENT - What is the meaning of the "Net" result printed from Surface Integrals command?
|When using the Surface Integrals command, FLUENT prints out the quantities in the console window: for example, the area-weighted average pressure on the "inlet' and "outlet"...|
FLUENT V6 - User-Defined Function (UDF) to report span-wise forces acting on an aircraft wing
|FLUENT can report the total force that is acting on the wing. But sometimes, it is required to know the spanwise report of forces acting on that wing. This can be achieved by using the UDF...|
FLUENT V6 - Possible cause and resolution for the message: "Warning: no x, y or z points specified in profile"
|When reading a profile into FLUENT a warning message is displayed
Warning: no x, y or z points specified in profile
When reading profile files, FLUENT looks for the x, y and z coordinates in the...
FLUENT 6 - Tips for predicting vortex shedding with high Mach number and high Reynolds number flows in 3D
|Flow domains that contain constrictions such as orifice plates may produce high Reynolds number and high Mach number flows with vortex shedding. This solution provides solution strategy tips for...|
FLUENT 6 - Improving convergence of calculations involving porous media with high resistance in the flow direction
|In calculations that involve porous media with high resistance in the flow direction, a good initial guess for pressure upstream may be necessary to ensure mass balance and good convergence. But...|
FLUENT 6 - Body Force Weighted discretization for Pressure recommended with the Non Iterative Time Advancement (NITA) scheme for VOF free surface calculations
|When the VOF free surface model is used, the PRESTO discretization scheme for Pressure does not work well in combination with the Non Iterative Time Advancement (NITA) scheme.
The Body Force...
FLUENT 6 - Tips for converging the VOF free surface model with the Non Iterative Time Advancement (NITA) solution scheme on tetrahedral meshes
|It has been observed that some calculations that include the VOF free surface model with surface tension and the Non-Iterative Time Advancement (NITA) solution scheme on tetrahedral meshes...|
FLUENT 6 - On the fly monitoring of maximum/minimum values of any variable in the domain
|Many times while running cases, it is required to monitor the maximum/minimum values of some variables like temperature, pressure, turbulence quantities etc. in the domain. These values cannot be...|
FLUENT - How to create animations of particle tracks?
|For a steady state flow simulation, how do I create an animation of particle tracks?
In FLUENT you can display the particle tracks in pulse mode. However, FLUENT doesn't have an inbuilt...
POLYDATA - Finite element interpolation for velocity in POLYFLOW?
|What finite element interpolation is recommended for the velocity field in POLYFLOW?
Usually, the following recommendations are made:
- 2D without slip: quadratic velocity with...
POLYFLOW - loss of convergence for Darcy flow through a non-isotropic porous media
|When defining a non-isotropic porous media, e.g. with Pxy = Pyy = 0 for a 2D case, the calculation may diverge and shows oscillatory behaviour in the Darcy pressure.
When changing Pyy = 1e-12...
blower modeling in Fluent
|(1) Mesh Size
Don't under-resolve the blower. Make sure you have enough cells to adequately resolve all of the relevant geometry (e.g. blades, hub and shroud surfaces, etc.). Typical blower...
Modeling thermostat cycle operation in Airpak
|How we can simulate following problem in Airpak:
Whenever the room temperature went above a certain value, Airpak turned
off the heating air supply in the room. Likewise, if reached below...
FLUENT 6 - Write pressure gradient history in a file (obtained from a translational periodic case)
|It is possible to monitor pressure gradient (pressure drop/unit length) as a function of iteration.
This can be done in the following panel:
Solve-> Monitor -> Statistics
However writing this...
POLYFLOW - The absolute pressure at the exit does not seem to match the selected boundary conditions
|In a 3D calculation, the absolute pressure at a die exit does not seem to match the assigned boundary condition. Is there a way to find a gauge/absolute pressure at the exit of a channel
UDFs to implement pressure-drop vs massflow rate data (in a given direction) for a fluid zone
|This solution describes a UDF that can be used for easy setup of 1D resistance
inside a fluid zone given the pressure-drop vs massflow data (for a direction) in tabular format.
One approach to do...
Cavitation model with dynamic mesh doesn't converge!!! -- FLUENT-6.2
|Cavitation model with dynamic mesh doesn't converge!!! The case carries pressure bcs.
It is often found that cavitation model is not converging. This is also found true when dynamic meshing is...
An explanation of how the gravitational body force term is formulated in FLUENT
|Questions have arisen from time to time about how FLUENT 6 treats the gravitational body force term. A derivation and explanation of this is provided in the pdf document (below).
Profile of fixed value in a fluid zone using a DEFINE_PROFILE function
|It is possible to implement an analytical profile of fixed values to the fluid zone. But the DEFINE_PROFILE function has to be modified a little bit to fit the loop over all the cells. The...|
How much memory is required for my simulation?
|The user would like to estimate how much memory would be required for a given mesh size.
The following numbers are for a linear mesh using the segregated iterative solver. The numbers are, of...